Signaling



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Dec. i8 E923,

H. AFFEL SIGNALING Filed March so. i920 fomv . Rf 'a SLOW MHG'INL RELAY l l l ATTORNEY 45. the same apparatus may be Patented @en i8, i923.

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HERMAN A. AFFEL, 0F BRGOKLYN, NEW YORK, ASSIGNOR TO AMERICAN TELEPHONE ANI) TELEGRAPH COMPANY, A CORPORATIGN OF NEW YORK. Y'

Y SIGNALING.

Application led March 30, 1920. Serial No. 369,979.

T 0 all whom t may concern.'

Be it known that I, HERMAN A. Arm residing at Brooklyn, in the county of Kings and State of New York, have invented certain Improvement-s in Signaling, of which the following is a specification.

This invention relates to' signaling and is vdescribed herein with particular reference tomethods of Vand means for transmitting and receiving ringing signals in telephone transmission systems, although its application is not limited to such systems.

In present day telephone and telegraph practice, it is customary to provide a trans mission system with a plurality of channels each of which serves to transmit current independently of the others. between the various channels is prevente by employing for each, different frequencies or bands of frequencies and apparatus selectively responsive thereto. The frequency range Vis thus divided into a number o levels and a separate transmission channel is provided foreach frequency level. Two of the channels used in telephone practice are the voice channel and the ringing channel, the frequency level of the latter being generally below that of the former. In present `usual practice, for example, the

,ringing currents have a frequency of 135 cycles, whereas the components of the voice current have frequencies varying from about 300 to 2000 cycles.

This arrangement necessitates at repeater and similar installations the provision of separate repeating or relaying apparatus for the ringing and voice currents, for the reasonY that the coils and amplifiers eificient at voice frequencies are ,ineliicient at the ringing', .frequency and lvice versa. My

V.present -inventionproposes to do away with' this duplicationl of apparatus by raising the ringing channel to the same frequency level. as that of the voice'channel, so that eiiciently employed for the transmission of the currents of both.

To prevent false operation of the signaling apparatus by the voice currents, I propose in the present invention, to employ a plurality of signaling currents diifering in frequency and a .plurality of translating devices selectively responsive to these frequencies. The operators signal is arranged to respond only when both of these selec.

Interference d Vwhich are herein illustrated as connected in tive devices are simultaneously in an actuated condition.

A good understanding of the invention may now be had from the following descrip- Vtion thereof, having reference to a specific form of embodiment of the invention, shown in diagrammatic view in the accompanying drawing.

In this drawing reference character L1 designates a telephone line whichV is associated by the back contacts of a relay K with switchboard conductors l and 2, which in turn are associated by the back contacts of a relay II, with the usual operators answering jack and signal device (not shown). The front contacts of the relay K are associated with generators Gr, and Gr2 series with each other, and assumed to have frequencies of 300 and 700 cycles respectively,

other frequencies may be employed. The

circuit of the relay K is controlled by meansl of* a relay B, which in turn is controlled by the relay A. The last mentioned relay is bridged across conductors 1 and 2 and arranged to respond to current applied to the switchboard conductors l and 2 when the operator actuates the ringing key of the cord, as'usual in the art.

The signal receiving apparatus comprises relays R1 and R2, which are bridged across switchboard conductors 1 and 2, the circuit or It, being tuned to 300 cycles and that of It, to 700 cycles by means of the condensers shown in the drawing. The relays govern contacts 3 and 4, which are of the vibrating reed type, the contact 3 being arranged to respond only to current of 300 cycles and the contact 4 to 700 cycles. These contacts are vconnected in'parallel with each other and governv they circuit of a relay M, which in turn governs the circuit of the relay H. By virtue of the parallel connection of the contacts 3 and 4 the circuit of relay M isv c it being understood, however, that" f other connections of the generators and 'the circuit of relay B, which closes its back Vf contact and causes thus the operation of the f relay K. This relay closes its front contacts and causes current from both `generators G, and G2 to How outA overy the line to the distant station, where it serves to actuate signal responsive apparatus which may be similar to that of the local station, the operation of which apparatus is described below.v The distant station is provided also with sources of 300 and 700 Vcycle currents `for vpurposes of signaling to the operator at the local station, and the apparatusfor applying these sources simlutaneously to the line may be similar to that just described for the local station. Y v

When the operator at the distant station causes vthe applicationof the 300 and 700- cycle currents to line L the same flow over the back contacts of relay K into the circuit of `relays R1 and R2 respectively. These relays operate their f contacts 3 4and 4c and break, thus, the circuit of the-#relay M which closes its back contact and causes the operation of the relay H. This relayV associates 16 cycle current with the conductors leading lto the operators signal and causes thus the vresponse of the operators signaling lamp.

Y =False voperation of the signals by the voice channel currents in the same linethe .apparatus of this channel having-been o-mitted from vthe drawing for sakeof simplicityis preventedby reason ofthe fact that the simultaneous presence of both signaling currents rin the line conductors is required nal. These currents, moreover, must be of certain mini-mum duration and amplitude in order -to "cause the actuation of relaysv R1 and Raj The frequencies of the lgenerators shouldbe far enough apart `andy non-multiples of each other in order-toprevent the 4response of one reed to current of the frequency of the other vAlthough the signaling frequencies are `herein assumed as `300 and 700 cycles, it is to be understood lthat any other suitable frequencies substantially within or `closevto thevoice' ranfre 'are also applicable inY the `practical operation ofthe `signaling systems of this invention.

Although -1 haveherein shown-#and deffsc-ribed'only one formfand arrangement of apparatus embodying the invention and only onerform of method for practicing the same, it vis readily understoodft-hat various changes and-modifications may befrnade ytherein Vwithin thek scope Aof vthe `following Vclaims without departing from f-th'e'spiritI .:and./.jsco'pev of this invention.

March 1920.

What I claim is: v 1. 1n a telephone system, composite ringing apparatus comprising a source of low source v0f a plurality of frequencies in the voice range, a signal device receptive to the low frequency and a second signal device responsive toy the plurality of Vfrequencies when said plurality of frequencies are reoei-ved simultaneously only, means associvated with the latter signal device for contransmitting apparatus comprising ja source of .a plurality ofufrequen'cies in the voice range and said receiving apparatus comprising devices lselectively responsive 'to eurrents ofrfsaid frequencies, a source of im'- ,pulses of different frequency, a relay.v controlled `b y said receiving apparatus :and

adapted Yto open the tele? 'hone' line` andconneet thereto the source o4 impulses of Vd'ili'erentfrequencyp andmeans for rendering said relay Vresponsive only .to the simultaneous operation of said selective devices. A

3. 4In combination, a telephoneline, signal transmitting and receiving apparatus associated with the terminals thereof, sai-'d transmitting apparatus comprising a source of a plurality --offrequencies in the-.voice range and said receiving apparatus comprising devices selectively responsive to currents Y of saidr frequencies, a source of 'low"fre to cause the responseof the operators sigrequency ringing 'current` and 4a .second v quency ringing current and a circuit conparatus comprising ar source .of low ffr'equency ringing cur rent}and asecond'source of a plural-ity roffrequencies 1nrv the volce range, a .signal ydevice responsive to the low frequency coming' from .the switchboard circuit, IV.a relay controlled therebyfand adapted, 'on operation, to connect said source of `voice frequencies to ythe line,y a .relay. responsive. to thesimultaneous .receipt ,ofa ,plurality fof. 'voice vfrequenciesfonly,a relay controlled thereby and itself adapted to interrupt Cthe voice channel and. connect'theretothewlow frequency .ringing source.

In l .testimony fwhereof .1, havereigned my v nameA to `this specification .thisrf29th fdayof HERMAN-AEFEL 

